Tube and package making methods

ABSTRACT

A method is provided of forming a tube from a flat web of material including the steps of: PROVIDING A WEB HAVING AT LEAST SEALABLE EDGE PARTS; MOVING THE WEB AROUND THE SURFACES OF A TUBE FORMING MEANS TO FORM A TUBULAR STRUCTURE WITH AT LEAST THE SEALABLE EDGE PARTS IN OVERLAPPING RELATIONSHIP WITH EACH OTHER; BONDING THE OVERLAPPING EDGE PARTS TOGETHER AND PASSING THE TUBULAR STRUCTURE ALONG THE OUTER SURFACE OF THE TUBE FORMING MEANS AND AROUND A LIP OF THE TUBE FORMING MEANS AND INTO THE INTERIOR THEREOF TO FORM A TUBE RECEPTIVE FOR FILLING. The overlapping edge parts of the tubular structure are sealable by pressure, or heat if desired, and the movement of the tubular structure is under tension so as to provide the forces necessary to align and assist in sealing the overlapping edge parts as the tubular structure is moved. A method also is provided of making a package using the tube described above including the further steps of: CLOSING THE FORMED TUBE AT ITS END; INSERTING AN ARTICLE IN THE TUBE; FORMING A CLOSURE IN THE TUBE ADJACENT TO THE ARTICLE; AND SEVERING THE TUBE ADJACENT TO THE CLOSURE TO FORM A PACKAGE. The tube may be evacuated of air prior to closing the portion of the tube adjacent to the article and the closed tube may then be shrunk into contact with the article to form a shrink package.

United States Patent Lesher Dec. 18, 1973 TUBE AND PACKAGE MAKING METHODS Herbert A. Lesher, Claymont, Del.

E. l. du Pont de Nemours and Company, Wilmington, Del.

22 Filed: Feb. 22, 1972 211 Appl. No.: 228,276

[75] inventor:

[73] Assignee:

[52] [1.8. Cl. 53/28, 53/22 A [51] Int. Cl B65b 9/08 [58] Field of Search 53/28, 22 A [56] References Cited UNITED STATES PATENTS 2,951,322 9/1960 Wood 53/28 2,607,696 8/[952 Kunz 53/28 X 2,145.94! 2/!939 Maxficld 53/22 A 2.801.180 7/1957 Rumsey 53/30 X l.546.36i) 7/1925 Bates. 53/28 Primary ExaminerTravis S. McGehee Att0rneyHoge T. Sutherland [57] ABSTRACT A method is provided of forming a tube from a flat web of material including the steps of:

providing a web having at least scalable edge parts; moving the web around the surfaces of a tube forming means to form a tubular structure with at least the scalable edge parts in overlapping relationship with each other; bonding the overlapping edge parts together and passing the tubular structure along the outer surface of the tube forming means and around a lip of the tube forming means and into the interior thereof to form a tube receptive for filling.

The overlapping edge parts of the tubular structure are sealable by pressure, or heat if desired, and the movement of the tubular structure is under tension so as to provide the forces necessary to align and assist in sealing the overlapping edge parts as the tubular structure is moved.

A method also is provided of making a package using the tube described above including the further steps of:

closing the formed tube at its end; inserting an article in the tube; forming a closure in the tube adjacent to the article;

and severing the tube adjacent to the closure to form a package.

The tube may be evacuated of air prior to closing the portion of the tube adjacent to the article and the closed tube may then be shrunk into contact with the article to form a shrink package.

1 Claim, 8 Drawing Figures PAIENIE um 8 197a sum 1 BF 3 FIG.

FIG-2 PATENTED 3 778 961 SHEEI 2 BF 3 TUBE AND PACKAGE MAKING METHODS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is a tube forming and package making method and, more particularly, is directed to a novel method of forming a tube from a flat web of heatshrinkable material having scalable edge parts and of packaging an article or contents in such tube to make a shrink package.

2. Description of the Prior Art Packaging arrangements and tube forming and package making apparatus and methods of this general type are old.

It is known, as exemplified in U.S. Pat. No. 2,890,552 to Henderson, to skin-package articles such as hams and eviscerated poultry by forming a pouch or bag from a flat web or a seamless tube, inserting the article into the pouch, evacuating the interior of the pouch, sealing its mouth portion and heat shrinking the pouch into conformity with the shape of the article being packaged.

U.S. Pat. No. 3,5 14,165 to Greenwell teaches a method of and apparatus for packaging articles in heatshrinkable film by separating a tube of such film wrapped around spaced groups of the articles (by shrinking the tube along a weakened zone) and then by shrinking the tube section formed thereby around an article group to form a shrink package.

U.S. Pat. No. 3,380,220 to Jennings et al. discloses a plastic bag tree packaging method including placing a supply of tubular material upon the exterior surface of the tubular element and intermittently drawing tubular material from this surface and into such tubular element for the purpose of enclosing a tree being passed therethrough. The tree movement draws the prefabricated tube stock from the outer surface of the wrapping sleeve so that it will automatically encircle or enclose the tree. When the supply of tubular material on the tubular element is exhausted, the empty tubular element is moved to a loading station where a new supply of tubular material is placed on it.

In the apparatus and methods described in these patents, as in other apparatus and methods of the known prior art, the tube forming and package making operations are either not continuous, require additional steps or parts or do not provide the total, practical, utility found in the instant tube forming and package making method of this invention, as will become apparent.

SUMMARY OF THE INVENTION In the method of the instant invention, the tube is formed from a flat web having at least sealable edge lanes by passing the web around and through a unique tube forming means. This tube forming means has an outer mandrel section about which the web is wrapped and reversed to pass within and adjacent to the outer surface of a cylindrically shaped inner mandrel. The edges of the flat web are brought into an overlapping relationship with each other by passing around and within the outer mandrel section and a seal is then effected to bond the overlapping edges of the web. The seals can be formed by combinations of pressure with a pressure-sensitive adhesive, heat with a thermoplastic adhesive, heat and pressure with nothing but the bonding of thermoplastic web lanes by their own substance and by combinations of the above.

The formed tube then passes over a part of the outer surface of the inner mandrel, around its lip portion and within the inner mandrel after being reversed l in flow path. This tube reversal permits the web to be formed into a tubular configuration in a minimum length path which procedure results in greatly shortened equipment requirements.

The passing of the partially formed tube around a portion of the outer surface of the inner mandrel and around the lip of the inner mandrel enables the web to be formed into a tube having uniform overlapping edge parts. The formed tube positioned within the inner mandrel is in an operative-packaging position for receiving an article to be packaged.

The open end of the positioned tube is gathered, crimped and banded with a formed wire or metallic band. The article to be packaged is then pushed into the closed-end tubing within the inner mandrel of the tube forming means so that it is positioned against the closed end. This movement of the article against the closed end of the tubing advances the tubing so that additional tubing is formed from the flat web by the tube forming means.

The packaging structure with the article in it is then evacuated of air, closed at the top end and severed from the tube to form a package. This package is preferably heated by impinging hot air on it or by placing the package in a hot water bath to shrink the web about the article and thus to form a shrink package.

The methods and apparatus known to the art do not provide these numerous interlocking advantages in tube forming and package making operations and it is this novel combination of steps that is the instant invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view of parts ofa package making apparatus for practicing the tube forming and package making methods of this invention.

FIG. 2 is a perspective view of parts of the apparatus of FIG. 1.

FIG. 3 shows, in greater detail, an adhesive applying means of the apparatus of FIG. 1.

FIGS. 48 show steps of the package making method of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The method of this invention is designed to seal overlapping parts of plastic film having scalable edge parts to form a tube without damaging the material during the sealing operation. The tube is formed using novel tube forming steps and is positioned to receive an article in making a package.

Referring to FIGS. 1 and 2 in particular, there is shown an apparatus suitable for the practice of the tube forming and packaging making method of this invention.

Briefly described, a preferred tube forming method of the invention includes the steps of:

moving a web from a supply source and into operative relationship with a tube forming means;

applying an adhesive along at least one edge part of the web as it moves toward the tube forming means;

moving the web over and around the forming surfaces of the tube forming means whereby to form an open-ended tubular structure with edge parts of the web in overlapping relationship with each other and with the adhesive positioned therebetween;

moving the tubular structure, under tension, in a first path along and in sliding contact with an outer surface of the tube forming means and toward a first end opening thereof; and

moving the tubular structure, under tension, around the lip defining the first end opening of the tube forming means and in sliding contact therewith and then in a second path through the inside of the tube forming means whereby the movement of the web along the first path along the surface of the tube forming means and around the lip of the first end opening of the tube forming means and in the second path through the inside thereof, under tension, provides sufficient pressure to enable the adhesive to seal the overlapping edges of the tubular structure together to form a tube.

A preferred method of making a package of this invention includes the steps just described of forming a tube, plus the additional steps of:

moving the tube beyond a second end opening of the tube forming means;

securing parts of the tube together adjacent the second end opening of the tube forming means to form a first packaging structure having a bottom closure;

inserting an article into the open end of the first packaging structure and into contact with the bottom closure;

pushing the article against the bottom closure to move the first packaging structure in the first path and at least a package length beyond the second end opening of the tube forming means wherein such pushing moves the web along the first path and in sliding contact with the outer surface of the tube forming means to form more open-ended tubular structures with edge parts of the web in overlapping relationship to each other and moves the tubular structure around and in sliding contact with the lip of the first end opening of the tube forming means and, then, in the second path inside the tube forming means thereby to form more tube;

evacuating air from the first packaging structure having the bottom closure and having the package unit therewithin;

securing parts of this first packaging structure together adjacent the second end opening of the tube forming means to form a first packaging structure having a top closure;

securing parts of the tube together adjacent the second end opening of the tube forming means to form a second packaging structure having a bottom closure;

severing the first packaging structure having the top and bottom closures from the second packaging structure having the bottom closure to form a package; and

shrinking the first packaging structure having the top and bottom closures into contact with the package unit to form a shrink package.

In practicing the method of this invention, a web of material, shown in H6. 1, such as thermoplastic film, is supplied from a supply source ll and moved by manual or appropriate mechanical means, not shown, into operative relationship with a tube forming means, generally designated 20. The supply source may be any appropriate source, for example, it may be a web of thermoplastic film wound onto a windup roll, as shown. From the supply source 11 the web 10 first passes around a guide roll 12, into operative association with an adhesive applying means 30, if used, around a guide roll or bar 13 and into operative association with the tube forming means 20.

The adhesive applying means 30 is preferably employed in the practice of the method of this invention when webs are used that are not readily heat-sealable such as polyethylene terephthalate webs. This adhesive applying means 30, as best shown in FIG. 3, includes a stationary adhesive applying roll 31 having an adhesive passageway 32 and an adhesive slot 33 therein for feeding adhesive adjacent to the edge of the web 10 along a path in its undersurface as the web is moved over roll 31. A uniform path of adhesive is applied to the web as the web passes over the vertical column of adhesive contained in the adhesive slot 33. The flow of adhesive is assured due to the head pressure of the adhesive within the adhesive passageway 32 and to the capillary attraction between the adhesive and web materials. Such flow occurs whenever the web 10 passes by the opening in the adhesive slot 33. This application of adhesive is successfully accomplished for both continuous and intermittent operation such as is normally experienced in the packaging method of the instant invention. To provide adequate and uniform movement of the web over the roll 31, there may be provided a pressure means for pressingly positioning the web 10 against the roll 31 adjacent the slot 33, such pressure means preferably being in the form of an air stream 34 supplied from an appropriate source through openings in an air pressure supply means 35. The air supply means 35 is preferably shaped to have a bottom surface matching the top surface of the supply roll 31 and the supply means 35 may be provided with a control means 36 for regulating the air pressure supply. This adhesive applying means 30 is adapted to apply an adhesive, preferably a pressure-sensitive or heat-sensitive adhesive, along at least one edge part of the web 10 as it is moved and moves toward the tube forming means 20. Other means and methods may be used for applying a suitable adhesive to the edge portions of the web 10, or, if desired, the web 10 itself may be of the type that has an inherent sealable edge part or, if desired, the web 10 may be coated with a scalable material over its entire surface. For example, the web may be polyethylene or a coated thermoplastic material with an adhesive strip adjacent one edge.

The tube forming means 20, as best shown in FIG. 2 and FIG. 4, plays a key role in the practice of the method of this invention. Such forming means 20 includes an inner mandrel 21 and forming surfaces 22 adapted to accept the web 10 to start shaping the web 10 into a tubular configuration. The web 10 passes around the forming surfaces 22 of tube forming part 23 and then is reversed around tube shaping edges 24 and passed under forming surfaces 22 and around the outer surface of the inner mandrel 21.

The tube forming means 20 is adapted to form an open-ended tubular structure with edge parts of the web 10 in overlapping relationship with each other (as shown in 10' in FIG. 2 and FIG. 4) and with the adhesive material previously applied positioned therebetween. Various teachings of the prior art may be used to form the flat web into this opemended tubular structure; for example, U. S. Pat. No. 3,486,424 to Tanner and U. S. Pat. No. 1,313,234 to Jones show comparable tube forming devices for accomplishing this step.

The tube forming means 20 has a first end opening 25 and a second end opening 26, as shown in FIG. 2. The first end opening 25 of the tube forming means 20 is defined by a continuous lip 27 as shown in FIG. 1 (parts of the web have been broken away to show this). The forming surface 22, the outer surface of inner mandrel 21 and the lip 27 of the inner mandrel 21 play key roles in the practice of the method of this invention. The web 10 with the edge parts in overlapping relationship with each other forming the tubular structure is moved over and around the outer surface of the inner mandrel 21 and toward the first end opening 25 of the tube forming means. In the first path P-l, the tubular structure is moved, under tension, around and in sliding contact with the lip 27 of the inner mandrel 21, within the inner mandrel 21 and toward the second end opening 26 thereof. This contacting movement of the tubular structure along the lip 27 maintains the alignment of the overlapping edge parts and in some cases completes the sealing of the overlapping edge parts of the tubular structure. Such movement is under tension and sealingly presses the overlapping edge parts of the web 10 together and effectively maintains the overlap in aligned relationship as the web is moved through the tubeforming means either manually or by mechanical means.

As stated, the tubular structure is moved over and around the lip 27 defining the first e'nd opening and in sliding contact therewith and is then moved in a second path P-2 through the inside of the tube forming means 20 forming a tube T having a longitudinal seal S therealong. In certain sealing operations, the sliding contacting movement of the overlapping parts of the tubular structure with the lip 27 completes the seal; in other sealing operations, the tension created by the movement of these overlapping edge parts around the lip 27 provides sufficient pressure during the movement of such overlapping parts along the outer surface 22 of the tube forming means 20 to complete the seal. In all cases, the sliding movement of these overlapping parts around the lip 27 distributes the forces equally back along the tubular structure and this distribution maintains the alignment of the edges of the tubular structure in overlapping contact. This is so even if unequal forces which would normally distort or disrupt this overlap are present due to pulling or moving of the tubular structure into the tube forming means 20 or as a result of unequal forces being placed on the bottom closure of a packaging structure formed from the tube during a packaging operation, as will later be explained in greater detail.

This reverse forming of the tubular structure around the lip 27 and into the inner mandrel 21 is the touchstone of the method of this invention. The tubular structure is formed equally as well either continuously or intermittently by the reverse forming step in the method of this invention in which the tubular structure is moved from the first path P-l around the lip 27 of the inner mandrel 21 and turned 180 into the interior of the inner mandrel 21 and then moved in the second path P-2 therewithin. This movement takes place with the web being under tensile loading. The tension supplied by moving the tubular structure around the lip 27 and in sliding contact with it and into the tube forming means is an effective means of keeping these edge parts in overlapping relationship with each other without use of pressure devices or wheels, for example.

This tube forming step or steps, while novel and unobvious in and of itself, accomplishes another desired result in that it positions the tube so formed, without further movement, and with the parts effectively and completely sealed, in a package making position ready to receive a package to be loaded, as will now be explained.

In the package making method, the steps just described provide a package maker with an open-ended tube T formed from a flat web 10' in position to receive an article, such as a primal meat cut, not shown. In such position, the tube T is held in open mouth position by the lip 27 of the tube forming means 20 which now also serves as a chute, funnel or tube positioning means for assisting in guiding the article into a package structure formed from the tube.

The first step of the package making method is the moving of the tube T in the second path P-2 through the interior of the tube forming means 20 and beyond the second end opening 26 of such tube forming means, by appropriate means or manually. It is important to observe that this movement draws more material from the supply source 11 and through the tube forming means 20 in the manner as previously described.

After the tube T has been moved beyond second end opening 26, as shown in FIG. 4, parts of the tube T are then secured together adjacent such second end opening 26, as shown in FIG. 5, to form a first packaging structure having a bottom closure C-l. Such closure C-l may be accomplished by gathering the parts of the tube T together adjacent the second end opening 26 and by clipping the gathered together parts by appropriate clip applying means, such as shown at 40 in FIGS. 1 and 2.

With the bottom closure C-1 of first packaging structure 100 thus formed, an article is inserted into the open end thereof and into contact with the bottom closure C1. The package unit is then pushed against this bottom closure C-l to move the first packaging structure 100 in the second path P-2 and at least a package length beyond the second end opening 26 of the tube forming means. Such pushing moves or draws the web 10 from the supply source 11 along the first path P-l, through the tube forming means 20 and then in the second path P-2 inside the tube forming means 20 thereby to form additional tubing. This packaging step of pushing at least the package length of tubing beyond the second end opening 26 forms an additional package length of tubing and positions it ready to receive a subsequent package unit.

A suitable means for pushing an article into the open end of the tube T and through the tube forming means 20 which in this instance is serving as a part of a package forming means, may be in the form of a pusher and evacuating means 50, as shown in FIGS. 1 and 2.

After the article has been pushed against the bottom closure C-1 and the first packaging structure 100 pushed through the second end opening 26 of the tube forming means, air is preferably evacuated from the first packaging structure by the air evacuation means 50 and a top closure O2 is formed by securing parts of the first packaging structure 100 together adjacent the second end opening 26, as shown in FIG. 6.

At the same time, a bottom closure 01 may be formed for a second packaging structure 200 by securing together parts of the tube T adjacent the top closure 'C-1 of the first packaging structure 100, again as shown in FIG. 6.

Following this the first packaging structure 100 having first and second bottom closures C-1 and C-2 and having air evacuated from around the article in this packaging structure 100 is severed from the tube T just below the bottom closure C-1 of the second packaging structure 200, as shown in FIG. 7. it is noted that the second packaging structure 200, after the severing has taken place, is in package position for repeating the steps just described in forming a package or another packaging structure.

Lastly, the first packaging structure 100 is placed into boiling water, or is subjected to heat, to shrink the packaging material into contact with the package unit to form a package P, as shown in FIG. 8.

This completes the tube forming and packaging making steps of this invention.

The web material that can be used to form the tube and package of the present invention comprises one or a laminate of one or more organic thermoplastic polymeric materials. Generally applicable polymeric films are those manufactured from polyethylene terephthalate, polyethylene, polypropylene, polyamides, polyvinylidene chloride copolymers, ethylene/vinyl acetate copolymers, polyvinyl chloride and crosslinked ionic copolymers. The preferred film is an 0.8 mil thick oriented polyethylene terephthalate web. in many applications, it is preferred that the thermoplastic film employed to fabricate the tube and package be heat shrinkable to an extent sufficient to permit the material to conform to the general contours of the article being packaged. The thermoplastic film employed, whether heat-shrinkable-or not, can also be coated with coating materials commonly employed in packaging, such as Saran coatings.

As previously described, the tube is formed by overlapping and sealing the thermoplastic film edge lanes together. When certain film types are employed, such as polyvinylidene chloride films, the web material has an inherent attraction and no auxiliary sealing means may need to be employed. In fabricating the tubes of this invention for most applications, however, a bond is formed between the overlapping film layers by a heat sealing means, an adhesive means and by combinations of both means. Heated bars and wheels are preferred for use in forming a heat-assisted seal.

Typical adhesives which can be employed in forming the bond between the overlapping film edges include polyester resin adhesives, polyvinyl acetate emulsions and hot-melt blends of petroleum wax and ethylene/vinyl acetate copolymers. A preferred adhesive is Du Ponts F. & F. No. 46961 polyester adhesive which is used in conjunction with a heated bar sealer.

l claim:

1. A method of making a package including the steps of:

moving a web from a supply source and into operative relationship with a tube forming means;

applying a pressure-sensitive adhesive along at least one edge part of the web as it moves toward the tube forming means;

moving the web over and around the forming surfaces of the tube means to form an open-ended tubular structure with edge parts of the web in overlapping relationship with each other and with the adhesive positioned therebetween;

moving the tubular structure, under tension, in a first path along and in sliding contact with an outer surface of the tube forming means and toward a first end opening thereof to start the sealing of the overlapping edge parts of the tubular structure together;

moving the tubular structure, under tension, around a lip defining the first end opening of the tube forming means and in sliding contact-therewith and then in a second path through the inside of the tube forming means to complete the sealing of the edge parts of the tubular structure together to form a tube whereby the movement of the web in the first path along the outer surface of the tube forming means and around the lip of the first end opening of the tube forming means under tension provides, without the use of other means, sufficient pressure to enable the pressure-sensitive adhesive to seal the overlapping edges of the tubular structure together to form the tube before it leaves the lip;

moving the tube beyond a second end opening of the tube forming means;

securing parts of the tube together adjacent the second end opening of the tube forming means to form a first packaging structure having a bottom closure;

inserting an article into the open end of the first packaging structure and into contact with the bottom closure;

pushing the article against the bottom closure to move the first packaging structure in the second path and at least a package length beyond the second end opening of the tube forming means, and wherein such pushing moves the web along the first path and in sliding contact with the forming surfaces of the tube forming means and the tubular structure around and in sliding contact with the lip of the first end opening of the tube forming means and, then, in the second path inside the tube forming means thereby to form more tube;

securing parts of the first packaging structure together adjacent the article to form a a top closure for the first packaging structure; and

severing the first packaging structure having the top and bottom closures from the tube to form a package. 

1. A method of making a package including the steps of: moving a web from a supply source and into operative relationship with a tube forming means; applying a pressure-sensitive adhesive along at least one edge part of the web as it moves toward the tube forming means; moving the web over and around the forming surfaces of the tube means to form an open-ended tubular structure with edge parts of the web in overlapping relationship with each other and with the adhesive positioned therebetween; moving the tubular structure, under tension, in a first path along and in sliding contact with an outer surface of the tube forming means and toward a first end opening thereof to start the sealing of the overlapping edge parts of the tubular structure together; moving the tubular structure, under tension, around a lip defining the first end opening of the tube forming means and in sliding contact therewith and then in a second path through the inside of the tube forming means to complete the sealing of the edge parts of the tubular structure together to form a tube whereby the movement of the web in the first path along the outer surface of the tube forming means and around the lip of the first end opening of the tube forming means under tension provides, without the use of other means, sufficient pressure to enable the pressure-sensitive adhesive to seal the overlapping edges of the tubular structure together to form the tube before it leaves the lip; moving the tube beyond a second end opening of the tube forming means; securing parts of the tube together adjacent the second end opening of the tube forming means to form a first packaging structure having a bottom closure; inserting an article into the open end of the first packaging structure and into contact with the bottom closure; pushing the article against the bottom closure to move the first packaging structure in the second path and at least a package length beyond the second end opening of the tube forming means, and wherein such pushing moves the web along the first path and in sliding contact with the forming surfaces of the tube forming means and the tubular structure around and in sliding contact with the lip of the first end opening of the tube forming means and, then, in the second path inside the tube forming means thereby to form more tube; securing parts of the first packaging structure together adjacent the article to form a a top closure for the first packaging structure; and severing the first packaging structure having the top and bottom closures from the tube to form a package. 